It is necessary in various areas of the art to transmit control signals from a central device to a plurality of decentrally distributed customer terminals. In the field of energy supply load management or tariff management can e.g. be carried out in that control signals for the tariff adjustment or for switching off are transmitted to specific terminals. This can take place, for example, by means of data transmission via the power network (powerline communication, PLC). The method of longwave based radio ripple control, which is described, for example in EP 1 479 260 B1, can also be used for this purpose. On a tariff change to be carried out for all customer terminals or for a subgroup thereof or on a switching on or off of individual devices associated with the terminals within the framework of load management, it is necessary that the corresponding control instructions are implemented within a relatively short time, for example in the range below ten seconds.
Conversely, it can also be desired to receive signals from the customer terminals at the central device. There are currently, for example, increased efforts to introduce the automated measurement of power consumption (smart metering) in the area of private households. The individual consumption data have to be transmitted in a manner secure against interception, secure against manipulation and with high reliability. For reasons of economy and due to legal radiation restrictions, it is generally not desired to provide a high performance transmission device at each of the numerous customer terminals to transmit the data to the central device. Existing systems for the management of a plurality of customer terminals are therefore disadvantageous either with respect to the transmission rate, the response behavior, the data security or the system costs and cannot, for example, effect an efficient management of load, tariff or consumption for wide distribution of terminals.
It is thus the object of the invention to enable such efficient management for a large number of terminals.
This object is satisfied by a method having the features of claim 1 as well as by a management system which can be operated in accordance with the method.